Directional aerial system



' June 30), 11938.

E. GREEN DIRECTIONAL AERIAL SYSTEM Filed Dec. 8, 1933 2 Sheets-Sheet lINVENTOR ERNEST GREEN ATTORNEY June 3m, 1936. E GREEN 2,045,987

DIRECTIONAL AERIAL SYSTEM Filed Dec. 8, 1933 2 Sheets-Sheet 2 @D A A A A7\ A A A T o o-'-@ c c c I L 0 0 I L (3:?) IE1 (at {"1 o I 0 G O /O O E1 A i O C O 0 T a A Z J INVENTOR o 0 o O O ERNEST GREEN ATTORNEYPatented June 30, 1936 UNITED STATES PATENT OFFICE DIRECTIONAL AERIALSYSTEM Application December 8, 1933, Serial No. 701,419 In Great BritainFebruary 23, 1933 14 Claims.

This invention relates to directional aerial systems and has for itsobject to provide an improved and simplified form of aerial systemsuitable for use as a so-called beam aerial, i. e. an

aerial adapted to radiate a directional beam of radiation.

The invention is particularly adapted for use on short waves in order toprovide a short wave directional beam aerial.

According to this invention a directional aerial comprises a pluralityof radiating elements and a plurality of feeder elements the radiatingelements extending substantially at right angles to the feeder elementsand the whole system being constituted by two wires or conductors joinedtogether at one end, each of said wires or conductors being arrangedsymmetrically with relation to the other and in such manner that inportions of said wires or conductors the currents substantially addtheir efiects so that these said portions constitute radiating elementswhile the currents in the other portions substantially neutralize theirefiects so that these other portions constitute feeder elements.

The invention is illustrated in the accompanying drawings, Figures 1 to'7 of which show various arrangements in accordance therewith.

Referring to Figure 1 of the drawings, there is shown an aerial systemwhich comprises two WiresUTSRQPONMLKandABC DE F G H I J K joinedtogether at K and arranged as shown in the said Figure 1 upon whichfigure are marked the various dimensions in terms of wave length. Itwill be noticed that with the exception of the portions L K, J K, allthe elements are effectively each one half the working wave length long,and the stationary wave distribution of current obtained when the wholesystem is excited as indicated by voltage applied between the terminalsU A will be as shown in conventional manner by the broken lines inFigure 1. The currents in BC, DC, QP, OP, HI,

JI, LM, NM, GF, EF, RS, TS, are in phase, so

that these portions constitute the radiating elements while the currentin AB being in opposite phase to that in UT and the current DE being inopposite phase to that of RQ and. the current in ON being in oppositephase to that of GH and the current in JK being in opposite phase tothat in LK, these elements constitute feeder elements. The direction ofmaximum radiation will, of 'course, be perpendicular to the generalplane in which the whole system lies, i. e., this system is a broadsidesystem.

A plurality of aerial systems, as illustrated in Figure 1, may bemounted side by side, as illustrated in Figure 2 which shows two suchsystems, insulated tension wires TI being provided for suspensionpurposes.

Arrangements as illustrated in Figure 1 are, of course, bi-directionalbut uni-directional qualities can be obtained in manner well known, perse, by providing a suitable reflector or curtain system which mayconsist of a second system similar to the main aerial system andsuitably tuned or independently excited.

Again, a suitable reflector may be constituted by an ordinaryarrangement well known per se, of half Wave elements and in either casethe reflector should be positioned approximately a quarter of theworking wave length behind the aerial system. Where a plurality ofsystems, as illustrated in Figure 1 are employed in combination, forexample as illustrated in Figure 2, they should, of course, all beenergized in phase and this is accomplished in Figure 2 by utilizing asingle feeding source.

Figures 3 and 4 show a slight modification of the system illustrated inFigure 1, and it is thought that the nature of this modification will beobvious from the figures in question. If an aerial system as shown inFigures 3 or 4 be excited by a voltage across the terminals S and A thecurrent distribution will be as shown in Figure 3, the members BC, DC,EF, GF, HI, JI, JK, LK, MN, ON, PQ, RQ, constituting the radiatingmembers and the remaining elements constituting the feeder members.Assuming that the aerial is mounted vertically, radiation will behorizontally polarized, and its main direction will be perpendicular tothe general plane of the system.

If, however, the terminals S and A be connected together and energizedby voltage applied between them and earth, as shown in Figure 4, adifierent current distribution as indicated in Figure 4 will be obtainedand the elements AB, SR, DE, PO, GH and ML will constitute the radiatingelements, the currents in the remaining elements being mutuallycancelling in their efiects. In this case, therefore, assuming theaerial system to be vertical, the radiation will be verticallypolarized.

By employing a voltage supply arrangement as illustrated in Figure 5 itis possible to employ an aerial system as shown in Figures 3 or 4 toradiate horizontally and vertically polarized waves independently.Activation of the aerial system for radiating horizontally polarizedenergy is obtained by energy delivered by the secondary WX of atransformer whose primary is energized from a suitable source I, thesecondary being connected between the points S A. Activation for V ,theaerial for vertically polarized voltage applied by means of atransformer whose primary is energized from a suitable source 2 andwhose secondary Z is connected between the center of WX and earth. 7

Since the systems in accordance with this invention areobviouslyutilizable either for radle ation or reception, aerials asshown in Figures 3 and 4 may be employedto receive vertically polarizedwaves and horizontally polarized waves independently, and suchaerialsare therefore ad- .vantageously applicable to so-called diversitytion withasystem as shown in Figures 3, 4 'or'5,

' whetherzthe system is. employed for horizontal or vertical polarizedradiation or both. If it be desired to radiate only horizontally or onlyvertically polarized waves a simple curtain ef half wave :lengthparallel tuned elements will constixtute a 'quite satisfactory reflectorfor either case,

and theseelements may be considerably less than ,aihalf'w'ave lengthapart.

Having "now particularly described and ascer- -tained"the"nature of mysaid invention and in what manner the same is to be'performed, I declarethat what -Ifclaim is:

1. A directional. aerial comprising aplurality of radiating elements anda:p1uralityjof feeder elements the radiating eiements extendingsubstantially at right angles to the feeder elements :and the Wholesystem being constituted by two conductorsjoineditogether :at one end,each of .said conductors being arranged symmetrically withrelation tothe other and in such manner that in portionsof said conductors thecurrents substantially add their eifects so that these said 7 portionsconstitute radiating-elements while the currents in the other portionssubstantially neutralize their effects "so that these other portionsconstitute feeder elements, the two conductors :heingarranged to proceedfrom one'e'nd parallel to one another for a distance. of substantially ahalf wave length, then turn each through a rightangleand proceed awayfrom one another for a distance approximately equal to a half wavelength, then turn each through two right angles and proceed towards oneanother for a distance approximately equal to a half wave length, thenturn each througha 'further'right angleand proceed .in the originaldirection for 'a distance substantially equal to a half wavelength,thetwoconductors being crossed over in this portiomthen turn eachthrough a right angle and proceed away from one another for a dis-;tancefiapproximatelyeqnal-to ahalf wave length,

and-so on, successive portions'of each conductor,

.excepttheend portion where the twoconductors join together, :beingapproximately a half wave length long, the .length -of. said "endportion being substantially ronequarter .of the Working wave and thewhole system. being constituted by two 7 conductors joined together atone end, each of said conductors being arranged symmetrically V withrelation to the other and in such manner that in portions of saidconductors the currents substantially add. their effects so that thesesaid portions constitute radiating elements While the currents'inthey-other portions substantially neutralize their effects so, thatthese other portions constitute feeder elements. the two conductorsbeing arrangedtoproceed from one end parallel to one another for adistance of substantially a half wavelength, turn each through a rightangle and proceed away from one another for a dis tance of approximatelya quarter wave length, turn each through two right angles and proceedtowards :one another for'a distance of approxi= mately one "quarter of awave length, turn each through aright angle and proceed in the originaldirection for :a distance of substantially a half wave length and so on.

3. In combination with an aerial as ciaimed in claim 2, a transmitterorzrecei'ver connected between earth and the first'mentioned ends of thetwo conductors.

4. The combination with an aerial as defined in claim 12, of anenergytran'sferring system consisting of a coil connected tothe'te'rminals of said aerial, a second coil connected between theelectrical center of said first mentioned coil and earth, athird-coilcoupled to the first coil and a fourth coil coupled to the second coil,the two last mentioned coils being each adapted to be connected to highfrequency apparatus. f

'5. A broadside antenna system comprising a pairaof closely spacedparallel horizontals other. similar pairs 01 parallel horizontals, eachhori-V zontal comprising two 'co linear portions, each portionbeinghot'substa ntially longer than onehalf wave length,;each:pair beingseparated'from the adjacent pair by 'a vertical "distance approxirhatelyone-half wave length, each co-linear-portion or each horizontal "beinga'radiating element and being connected at one end to the parallelcolinear :portion of the same'pair .at its adjacent 7 end, intermediatesubstantially'verti'cal elements one-half wave length llong forconveying energy from the 'radiatingelementsnof one horizontal to thoseof another, the last-mentioned vertical elementsbeingpositionedwithrespectto each other so as to neutralize radiation therefrom, andmeans iforaenergizingthesystem, whereby all horizontals areactivatediin-phase;

6. A system-as definedin claim 5 characterized V in this, that :eachc'o-linear pcrtion of each horizontal "comprises ;a conductorone-quarter wave I length long.

7. A system as defined in claim 5 characterized in this, that each'co-iine'arportion of each horizontal comprises a conductor one-halfwave length long, and includinga V shaped element,

' radiating elements and a plurality of feeder elements, theradiatingelements'extending substantiallyat' right angles to the feeder elementsand the whole system being constituted .by'two conductors joinedtogether ;at cm end, each of said conductors being arrangedsymmetrically with relation to the other and in such manner that inportions of said conductors the currents substantially add their eifectsso that these said portions constitute radiating elements while thecurrents in the other portions substantially neutralize their effects sothat these other portions constitute feeder elements, the two conductorsbeing arranged to proceed from one end parallel to one another for adistance of substantially a half wave length, then turn each through aright angle and proceed away from one another for a distanceapproximately equal to a half wave length, then turn each through tworight angles and proceed towards one another for a distanceapproximately equal to a half wave length, then turn each through afurther right angle and proceed in the original direction for a distancesubstantially equal to a half wave length, the two conductors beingcrossed over in this portion, then turn each through a right angle andproceed away from one another for a distance approximately equal to ahalf wave length, and so on, successive portions of each conductor,except the end portion where the two conductors join together, beingapproximately a half wave length long, the length of said end portionsbeing substantially one quarter of the working wave length, and asimilarly constructed aerial mounted side by side with said first aerialin a substantially vertical plane, both of said aerials being connectedin parallel to a common transmitter or receiver.

9. A plurality of aerials in accordance with claim 8, includingsuspension means comprising insulated tension wires mechanicallyconnecting adjacent ends of the radiating portions of the individualaerials.

10. An aerial in accordance with claim 1, including high frequencytranslating apparatus connected between the first mentioned ends of saidconductors.

11. The combination with an aerial as defined in claim 1, of a reflectoraerial consisting of a network of half wave length wires.

12. In an antenna system, a plurality of pairs of parallel horizontals,each horizontal comprising two co-linear portions, each pair beingseparated from the adjacent pair by a vertical distance approximatelyone-half wave length, each co-linear portion of each horizontal being aradiating element and being connected at one end to the parallelco-linear portion of the same pair at its adjacent end, intermediatesubstantially vertical elements one-half wave length long for conveyingenergy from the radiating elements of one horizontal of a pair to thoseof another horizontal of an adjacent pair, the last mentioned verticalelements being crossed over with respect to each other so as toneutralize radiation therefrom and to provide in phase energy to thehorizontals, and means for energizing the system.

13. A broadside antenna system comprising a pair of closely spacedparallel horizontals, other similar pairs of parallel horizontals, eachhorizontal comprising two co-linear half wave length portions, each pairbeing separated from the adjacent pair by a vertical distanceapproximately one-half wave length, each co-linear portion of eachhorizontal being a radiating element and being connected at one end tothe parallel 00- linear portion of the same pair at its adjacent end,intermediate substantially vertical elements one-half wave length longfor conveying energy from the radiating elements of one horizontal tothose of another horizontal of an adjacent pair,

the last mentioned vertical elements being positioned with respect toeach other so as to neutralize radiation therefrom, and means forenergizing the system whereby all horizontals are activated in phase.

14. A broadside antenna system comprising a pair of closely spacedparallel horizontals, other similar pairs of parallel horizontals, eachhorizontal comprising two co-linear half wave length portions, each pairbeing separated from the adjacent pair by a vertical distanceapproximately one-half wave length, each co-linear portion of eachhorizontal being a radiating element and being connected at one end tothe parallel colinear portion of the same pair at its adjacent end,intermediate substantially vertical elements one-half wave length longfor conveying energy from the radiating elements of one horizontal tothose of another horizontal of an adjacent pair, the last mentionedvertical elements being positioned with respect to each other so as toneutralize radiation therefrom, and means for energizing the systemwhereby all horizontals are activated in phase, and a U shaped element,the legs of which are one-quarter wave length long, on top of saidantenna for connecting together the two colinear conductors of thetopmost horizontal.

ERNEST GREEN.

